1. Field Of The Invention
The invention relates to printing control and more particularly to printer control in a processing system that performs document handling and formatting independent of the source of print data and of the printing device.
2. Description of The Related Art
In conventional computer systems, printing is performed by a printing device coupled to a system processor under control of a print driver. The print driver is adapted to convert data processed according to an application program to print data acceptable by the printing device. Large scale systems may include a printer or a copier/printer that provides such document handling features as grouping, sorting and duplex copying. These document handling features are generally incorporated in mechanical structures of the printer or copier/printer.
Printers for small systems such as personal computers usually lack the mechanisms to provide automatic document handling and the user must manually, group and sort documents and must manually produce duplex copies by repeating the printing operation. Alternatively, some document handling features may be incorporated in application programs such as word processors. As a result, a user must select print features available in the printer or in each application but cannot be assured that a general group of document handling features are available for all applications and all printers that may be used.
In the Microsoft.RTM. Windows operating system (windows environment), the data for printing from an application is coupled to a windows print driver through a windows graphics device interface. The windows print driver, which includes a spooler, converts the application data from the graphics device interface to print data and the print data therefrom is sent to the spooler which, in turn, stores the print data and any inserted format commands for outputting to the printer. The windows spooler provides spooling for all application programs through the windows print driver and its functions are controlled by windows system commands rather than application commands.
The windows print driver operates to send commands to the spooler that control the paging performed by the printer. The commands sent to the windows spooler include OpenJob(), StartSpoolPage(), WriteSpool(), EndSpoolPage() and CloseJob() which cause the processor to store the print data from the windows printer driver in a predetermined order for printing. There are, however, no document handling commands that operate to perform document handling such as grouping of pages, sorting of pages, duplex copying and reversing page order. Such document handling features may or may not be included in the application or in the printer.